Horror Frog

Of all the frogs in the world, perhaps the
strangest named one is the horror frog!
It’s real name is Trichobatrachus
robustus .
Would you believe that this frog actually breaks its own bones, more
than likely when it is feeling threatened by someone or something, and these broken bones produced claws that
break through the frog’s toe pads.
Isn’t that grisly!

Apparently there are some salamanders that also
behave in this gruesome way, as they force their ribs through their skin to
produce protective barbs. And it is
thought that nine out of the eleven frogs that belong to a group known as Astylosternus also feel compelled to act in this very bizarre way! Most of these are native to Cameroon.

There are some frogs
that naturally have bony spines that protrude from their wrists, but this is
something different as they are there already and are not made on demand as it
were, as is the case with the horror frog.

When the T. robustus is resting, the claws found on the hind feet
only, are nestled inside a mound of connective tissue. A lump of collagen forms
a bond between the claw's sharp point and a piece of bone at the tip of the
frog's toe.

The other end of the claw is connected to a muscle. It is felt by
experts that when the frog is attacked, it tightens this muscle, which pulls
the claw downwards. The sharp point then breaks away from the bony tip and cuts
through the toe pad, emerging on the underside.
The end result may look like a cat's claw, but the breaking and cutting
mechanism is very different and unique among vertebrates. Also unique is the
fact that the claw is just bone and does not have an outer coating of keratin
like other claws do.

Unfortunately, experts are not sure yet what happens when the claw
retracts - or even how it retracts. It does not appear to have a muscle to pull
it back inside so the general thought is that it may passively slide back into
the toe pad when its muscle relaxes.
This is not known for sure, as most of the investigation done on these
horror frogs have been carried out on dead frogs. And as amphibians it would not be surprising if
some parts of the wound heal and the tissue is regenerated.

Males of the species, which grows to about 11 centimetres, also produce
long hair-like strands of skin and arteries when they breed as shown in the photograph. It is thought that the "hairs"
allow them to take in more oxygen through their skin while they take care of
their brood.

In Cameroon, they are roasted and eaten. Hunters use long spears and
machetes to kill the frogs, apparently to avoid being hurt by their claws.